using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.Collections;
using System.Linq;
using System.Runtime.Remoting.Metadata.W3cXsd2001;
namespace abloop
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<byte[], string> collisionTable = new Dictionary<byte[], string>();
            SoapHexBinary hexString = new SoapHexBinary();
            Random pseudoRNG = new Random();
            SHA256 hashSha = new SHA256Cng();
            for (int i = 0; i < 39506988; i++)
            //For a 50 bit hash, this number gives us a ~50% chance for collision.
            {
                byte[] byteContainer = new byte[8];
                byte[] fiftyBitHash = new byte[7];
                pseudoRNG.NextBytes(byteContainer);
                //Generate prng number to hash
                byte[] hashedBYTES = hashSha.ComputeHash(byteContainer);
                //Use SHA256 to hash prng number
                fiftyBitHash[0] = (byte)(((int)hashedBYTES[25]) << 6);
                fiftyBitHash[0] = (byte)((int)fiftyBitHash[0] >> 6);
                fiftyBitHash[1] = hashedBYTES[26];
                fiftyBitHash[2] = hashedBYTES[27];
                fiftyBitHash[3] = hashedBYTES[28];
                fiftyBitHash[4] = hashedBYTES[29];
                fiftyBitHash[5] = hashedBYTES[30];
                fiftyBitHash[6] = hashedBYTES[31];
                //Get the right 50 bits of the hash
                hexString.Value = fiftyBitHash;
                collisionTable.Add(byteContainer, hexString.ToString());
                //Add both to the dictionary
            }
            var k = collisionTable.GroupBy(p => p.Value).Where(p => p.Count() > 1).Select(p => p).First();
            //Find collisions using LINQ magic
            Console.WriteLine(k.Count());
            foreach (var item in k)
            {
                Console.WriteLine(item.Value);
                var xud = new SoapHexBinary(item.Key);
                Console.WriteLine(xud.ToString());
                //Print the lsb(50) hash and the bytes used for the collision
            }
            Console.ReadLine();
        }
    }
}